1. Technical Field
The present invention relates to a liquid discharging apparatus and a control method thereof.
2. Related Art
Heretofore, as such a kind of liquid discharging apparatus, an apparatus has been proposed including a printing head for ejecting ink, an ink tank accommodating the ink, a first ink channel for supplying the ink from the ink tank to a manifold of the printing head, a second ink channel for retrieving the ink from the manifold to the ink tank, an ink circulating pump installed at the first ink channel, an opening/closing valve installed at the second ink channel, a suction cap for covering nozzle surface of the printing head, and a suction pump connected to the suction cap via a suction pipe, wherein, when the ink is filled in the printing head, the nozzle surface of the printing head is covered by the suction cap and the opening/closing valve opens to rotatably drive the ink circulating pump, so that the ink circulates through a circulating channel composed of the first ink channel, the manifold, and the second ink channel (for example, see JP-A-2000-33714). In this apparatus, when the ink circulates through the circulating channel in order to fill the printing head with the ink, the rotation direction of the ink circulating pump is reversed only for a short time, which easily removes bubbles in the circulating channel and restrains a back flow of ink or bubbles in the circulating channel.
In the above liquid discharging apparatus, it is possible to prevent ink or bubbles from flowing backward, but in the case where the circulating channel has a location at which bubbles tend to stay (for example, a joint of each component of the circulating channel) when ink flows in a forward direction, the bubbles in the circulating channel may not be sufficiently removed.